Skip to content

Commit

Permalink
traps,xcb: Prefilter zero-area boxes when converting traps
Browse files Browse the repository at this point in the history 
The rectangular tesselation routines rely on the presuming that all the
boxes it has to handle are already filtered to remove empty boxes.

<< /width 800 /height 600 >> surface context
0.0848671 0 0 0.0848671 39.907812 5.608896 matrix transform
8 0 m 12.417969 0 16 3.582031 16 8 c 16 12.417969 12.417969 16 8 16 c
3.582031 16 0 12.417969 0 8 c 0 3.582031 3.582031 0 8 0 c h
clip
16 0 m 8 8 l 16 16 l h
clip
0 0 16 16 rectangle
fill

Triggers the error given a traps tesselator like cairo-xlib.

Reported-by: Henrique Lengler <henriqueleng@openmailbox.org>
Analyzed-by: Massimo <sixtysix@inwind.it>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=81699
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
  • Loading branch information
Chris Wilson committed Aug 23, 2014
1 parent 545444e commit 13a0952
Show file tree
Hide file tree
Showing 2 changed files with 35 additions and 22 deletions.
28 changes: 17 additions & 11 deletions src/cairo-traps-compositor.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1393,7 +1393,7 @@ boxes_for_traps (cairo_boxes_t *boxes,
cairo_traps_t *traps,
cairo_antialias_t antialias)
{
int i;
int i, j;

/* first check that the traps are rectilinear */
if (antialias == CAIRO_ANTIALIAS_NONE) {
Expand Down Expand Up @@ -1423,17 +1423,21 @@ boxes_for_traps (cairo_boxes_t *boxes,
boxes->chunks.size = traps->num_traps;

if (antialias != CAIRO_ANTIALIAS_NONE) {
for (i = 0; i < traps->num_traps; i++) {
for (i = j = 0; i < traps->num_traps; i++) {
/* Note the traps and boxes alias so we need to take the local copies first. */
cairo_fixed_t x1 = traps->traps[i].left.p1.x;
cairo_fixed_t x2 = traps->traps[i].right.p1.x;
cairo_fixed_t y1 = traps->traps[i].top;
cairo_fixed_t y2 = traps->traps[i].bottom;

boxes->chunks.base[i].p1.x = x1;
boxes->chunks.base[i].p1.y = y1;
boxes->chunks.base[i].p2.x = x2;
boxes->chunks.base[i].p2.y = y2;
if (x1 == x2 || y1 == y2)
continue;

boxes->chunks.base[j].p1.x = x1;
boxes->chunks.base[j].p1.y = y1;
boxes->chunks.base[j].p2.x = x2;
boxes->chunks.base[j].p2.y = y2;
j++;

if (boxes->is_pixel_aligned) {
boxes->is_pixel_aligned =
Expand All @@ -1444,18 +1448,20 @@ boxes_for_traps (cairo_boxes_t *boxes,
} else {
boxes->is_pixel_aligned = TRUE;

for (i = 0; i < traps->num_traps; i++) {
for (i = j = 0; i < traps->num_traps; i++) {
/* Note the traps and boxes alias so we need to take the local copies first. */
cairo_fixed_t x1 = traps->traps[i].left.p1.x;
cairo_fixed_t x2 = traps->traps[i].right.p1.x;
cairo_fixed_t y1 = traps->traps[i].top;
cairo_fixed_t y2 = traps->traps[i].bottom;

/* round down here to match Pixman's behavior when using traps. */
boxes->chunks.base[i].p1.x = _cairo_fixed_round_down (x1);
boxes->chunks.base[i].p1.y = _cairo_fixed_round_down (y1);
boxes->chunks.base[i].p2.x = _cairo_fixed_round_down (x2);
boxes->chunks.base[i].p2.y = _cairo_fixed_round_down (y2);
boxes->chunks.base[j].p1.x = _cairo_fixed_round_down (x1);
boxes->chunks.base[j].p1.y = _cairo_fixed_round_down (y1);
boxes->chunks.base[j].p2.x = _cairo_fixed_round_down (x2);
boxes->chunks.base[j].p2.y = _cairo_fixed_round_down (y2);
j += (boxes->chunks.base[j].p1.x != boxes->chunks.base[j].p2.x &&
boxes->chunks.base[j].p1.y != boxes->chunks.base[j].p2.y);
}
}

Expand Down
29 changes: 18 additions & 11 deletions src/cairo-xcb-surface-render.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2902,7 +2902,7 @@ _boxes_for_traps (cairo_boxes_t *boxes,
cairo_traps_t *traps,
cairo_antialias_t antialias)
{
int i;
int i, j;

_cairo_boxes_init (boxes);

Expand All @@ -2912,17 +2912,21 @@ _boxes_for_traps (cairo_boxes_t *boxes,
boxes->chunks.size = traps->num_traps;

if (antialias != CAIRO_ANTIALIAS_NONE) {
for (i = 0; i < traps->num_traps; i++) {
for (i = j = 0; i < traps->num_traps; i++) {
/* Note the traps and boxes alias so we need to take the local copies first. */
cairo_fixed_t x1 = traps->traps[i].left.p1.x;
cairo_fixed_t x2 = traps->traps[i].right.p1.x;
cairo_fixed_t y1 = traps->traps[i].top;
cairo_fixed_t y2 = traps->traps[i].bottom;

boxes->chunks.base[i].p1.x = x1;
boxes->chunks.base[i].p1.y = y1;
boxes->chunks.base[i].p2.x = x2;
boxes->chunks.base[i].p2.y = y2;
if (x1 == x2 || y1 == y2)
continue;

boxes->chunks.base[j].p1.x = x1;
boxes->chunks.base[j].p1.y = y1;
boxes->chunks.base[j].p2.x = x2;
boxes->chunks.base[j].p2.y = y2;
j++;

if (boxes->is_pixel_aligned) {
boxes->is_pixel_aligned =
Expand All @@ -2933,18 +2937,21 @@ _boxes_for_traps (cairo_boxes_t *boxes,
} else {
boxes->is_pixel_aligned = TRUE;

for (i = 0; i < traps->num_traps; i++) {
for (i = j = 0; i < traps->num_traps; i++) {
/* Note the traps and boxes alias so we need to take the local copies first. */
cairo_fixed_t x1 = traps->traps[i].left.p1.x;
cairo_fixed_t x2 = traps->traps[i].right.p1.x;
cairo_fixed_t y1 = traps->traps[i].top;
cairo_fixed_t y2 = traps->traps[i].bottom;

/* round down here to match Pixman's behavior when using traps. */
boxes->chunks.base[i].p1.x = _cairo_fixed_round_down (x1);
boxes->chunks.base[i].p1.y = _cairo_fixed_round_down (y1);
boxes->chunks.base[i].p2.x = _cairo_fixed_round_down (x2);
boxes->chunks.base[i].p2.y = _cairo_fixed_round_down (y2);
boxes->chunks.base[j].p1.x = _cairo_fixed_round_down (x1);
boxes->chunks.base[j].p1.y = _cairo_fixed_round_down (y1);
boxes->chunks.base[j].p2.x = _cairo_fixed_round_down (x2);
boxes->chunks.base[j].p2.y = _cairo_fixed_round_down (y2);

j += (boxes->chunks.base[j].p1.x != boxes->chunks.base[j].p2.x &&
boxes->chunks.base[j].p1.y != boxes->chunks.base[j].p2.y);
}
}
}
Expand Down

0 comments on commit 13a0952

Please sign in to comment.